Boiler furnace



July 31, 1928. 678,827

C. SCHILLINGER BOILER FURNACE Filed July 14, 1926 V Mg, 1;.QKIIIIIIIIIIIIIIIII INVENTOR. yaw W ATTORN Ill Patented July 31, 1928.

UNITED. STATES" PATENT OF ICE.

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Application filed m 14,

old' boilers that were set very low. In mostcases, however, the cost ofraising the boiler or the possible lowering of the floor in order toprovide room to install the stoker beneath the boiler is so high as tomake the 1nstallation prohibitive, and in many instances 1t impossibleto do either because of structural dificulties. Tnsome instances thistype of stoker has been installed under low set boilers with standardfurnace arrangement. but invariably the installation has provedineficient, particularly when burning the finer grades of anthracite,and t was not possible to obtain very hlgh ratmgs One of the objects ofthe present invention is to provide a furnace structure embodying atraveling or chain grate stoker which is adapted to be 1nstalled n-frontof the boiler setting so as to make 1t unnecessary to either raise theholler or lower the floor, and which is simple 1n construct on, and ofhigh eficiency and great ilexiblhty, and in which complete combustion isinsured ,together with very low ash pit loss.

Another object of the invention is to provide a novel and improvedmethod of promoting combustion which is part cularly adapted for usewith traveling or chain grate stokers.

The several features of the invention, whereby the above mentioned andother objectsmay be attained, will be clearly understood from thefollowing description and accompanying drawing in which the figure is alongitudinal sectional view, partly diagrammatical, of my improvedfurnace structime My improved furnace structure, as illustrated in thedrawing, is particularly adapted for use with an old boiler Where it isdesired to substitute a traveling or chain grate stoker for the stokerpreviously used. The combustion chamber of the stoker is indicated 2 andthe chamber of the boiler is indicated at 4;. The Stoker may be of theusual construction having a chain grate 6, and a plurality of air supplycompartments 8 arranged between the runs of the chain for supplying airunder pressure to the up 1926. Serial in.- 122,293.

per run, the air supplies to the several compartments being separatelycontrolled.

As shown, the traveling rate is arranged in front of the boiler .cham erwith'its rear end spaced a distance from the front wall of saidchamberto provide a space throu h which the ashes may be discharged fromt e grate. The combustion chamber is provided with a front wall 10 and ahorizontally arranged to wall or roof 12 extending to the front wal ofthe boiler chamber. The front wall 10 of the combustion chamber isverticall arranged and its lowerportion is inelined downwardly andforwardly to provide an ignition arch 14 extending to the upper edge ofthe fuel receivin opening 16,

a fuel hopper 18 being provide which leads I into said opening. v Thecombustion'chamber is further provided with a rear arch 20 which extendsfrom the front wall of the boiler chamber over a little more thanone-half the length of the grate. The underside of the rear arch isinclined upwardly and forwardly with its rear end portion arranged inproximity to the grate. The forward .end of the under side of the archis curved in an arc to the front end of the arch which extends upwardlya distance parallel with the front wall of the combustion chamber.

The top side of the rear arch and the opposed under side of the top wallor roof of the combustion chamber define a passage leading from thespace-above the front end portion of the grate to the combustionchamber, a gas inlet opening being provided in the front wall of theboiler chamber which extends between the rear end of the top wall orroof of the combustion chamber and the rear end of the arch. The rearportion of the roof of the combustion chamber isarranged horizontallyexcept for its extreme rear end which is curved in an arc to the innerside of the front wall of the boiler chamber. The correspondingrearportion of the top side of the rear arch is' inclined rearwardly anddownwardly at a considerable angle so as to provide a rearwardly flaringexpansion space between said corresponding rear portions of the roof andarch. The remaining portions of saidwalls of the pasage are arrangedparallel and are in-.

clined slightly downwardly and rearwardly except for the forward endportions thereof which are arranged horizontally. The height of thespace between the bridgev wall A half the length. of the space betweenthe and the chamber roof, except between the rear portions thereof,-,issubstantially onefront wall of the combustion chamber and the front endof the rear arch.

With this arrangement, by admitting an -excessive amount of air to therear end portion of the grate, the low volatile ases gen'-.eratedbeneath the rear arch are b own for- 7 cause them to thoroughlywardly' with sufficient velocity through the restricted space beneath aair through the fuel bed are carried forwardinto the ash pit.

rear arc 15; by the high velocity under the rear arch to the front endof the stoker where the gas velocity is reduced very materially as-abovedescribed, which permits the particles to drop back upon the fuel bed atthis oint, thus materially aiding ignition and, 0 course, in creasingthe efiiciency. With the standard furnace these fine particles would beblown The s ace between, the to and the roof of t e combustion chamberis designed and shaped, and the gas velocity is high enough over thefront portion of the rear arch to keep the top service of the rear archswept clear of all fine ash and dust. This space or passage has aso-called Venturi effect, that is, the gases slow up as they reach theenlarged rear endof the passage and come nearer to the boiler, sothatthey will not im inge at too high a velocity against the boi er tubes,and also so as to give the fine ash carried in the gases time toprecipitate or drop down upon the rear end portion of the top surface ofthe rear arch, at which point means may be provided for easily removingthis fine ash.

' Also, with this arrangement practically any percentage of CO withinpractical limits can be maintained at the point Where the gases enterthe boiler by varying the amount of air admitted through the last orrearmost compartment of the stoker. It has been found that 17 per centumof CD, can be maintained continuously but the temperature at so high apercentage of CO is excessive, causing the refractories to melt, but byadmitting more air through the rearmost compartment, the CO can bebrought downto any desired point, and it has been found that from 14 to15 per centum of CO is as high as it is desirable to maintain. With.this construction of furnace it has side of the tense? been found to bepossibleto burn very fine sizes of anthracite, coal and at the same timeobtain higher ratings and higher efliciencies than it has been possibleto'do heretofore, and in most cases it is possible to install stokerswhere it would be im racticable to able, and the cost'in many instancesis less In the illustrated construction the rear do so if a standardfurnace on y were availarch. is made up of two walls 22 and 24 arrangedone over the other and spaced a distance apart with their front and rearends closed. Air under ressure is admitted in the s ace thus provi edbetween the two walls 0 the arch through a damper controlled opening 26which may be in communication with any suitable source of compressed airsuppliy. The air thus admitted to this space 1s ischarged through a duct28 leading to one of the air supply compartments 8 of the stoker,preferably the forward one. This air in passing through the spacebetween the two walls of the rear arch cools the steel work and castingssupporting the arch, and thus becomes preeated before it passes-tothe'stoker compartment where it is utilized to support combustion. Suchventilating or cooling of the rear arch is necessary because of theintense heat to which the arch is subjected on both sides thereof,

As will be evident to those skilled in the art, my invention permitsvarious modifications' without departin from the spirit thereof or thescope oft e appended claim.

What I claim is: A furnace of the class described having, incombination, a traveling grate, a boiler chamber at the rear of saidgrate, a front wall, a top wall arranged substantially horizontally andextending substantially over the length of the grate, and a rear archextending over substantially one-half of the length of the grate andarranged in proximity thereto, the forward end of said arch being spaceda distance from .said front wall to provide an expansion space, and thetop side of said rear arch together with the opposed portion of said topwall providing a restricted passage leading from said expansion space tothe boiler chamber, said arch being made up of two walls arranged oneabove the other and spaced a distance apart with the spaces betweentheir ends closed, means for admitting air under pressure to said spacebetween said walls of the arch, and means for discharging the air. afterpassing through said space beneath the ppper run of the grate to supportcombusion.

In testimony whereof, I have signed my name to this specification this12th day of July, 1926. A

CHRISTIAN SOHILLINGER.

